The latest drilling techniques for obtaining gas, which drill horizontally as opposed to the more traditional vertical drilling, shows a higher rate of leaking methane, according to a study that could spell problems for fracking across the nation.

After poring over data from the Pennsylvania Department of Environmental Protection involving more than 41,000 wells, it was determined that more than 6 percent of the active gas wells drilled in the Marcellus region of Pennsylvania “show compromised cement and/or casing integrity,” according to an academic paper published on Monday by the Proceedings of the National Academy of Sciences.

A team of four scientists – working without federal funding – conducted analysis on more than 75,000 state inspections of gas wells performed in Pennsylvania since 2000.

The results suggest that hazardous leaks of methane could pose potential obstacles for drilling across the nation, said study lead author Cornell University engineering professor Anthony Ingraffea, who leads an environmental activist group that helped subsidize the study.

The leak rate of methane was found in nearly 10 percent of horizontally drilled wells for before and after 2009 in the northeastern part of Pennsylvania, where fracking is a serious business.